John (Liberty) Bell wrote:

Oh No wrote:

Thus spake "John (Liberty) Bell"
Oh No wrote:

Thus spake Joseph Lazio
"J(B" =3D=3D John (Liberty) Bell =
writes:

JB John (Liberty) Bell wrote:
I think I've posted previously a reference to a paper that claimed
that Type II supernovae are difficult to detect beyond z ~ 0.5. The
most distant Type Ia supernova is about 1.7, IIRC.

Yes, that's right. SN1997ff is at z=3D1.755. In the Riess gold set the=
re
are only nine useful data points above z=3D1. Current surveys like the
Supernova Legacy Survey aren't even looking above about z=3D1, because=
of
measurement problems and risk of statistical bias in the data. We have
to wait for SNAP which should turn up hundreds, or even thousands of SN
at red shifts up to 2.

The reference (ApJ, 649, 563-569, 2006) provided by

(http://groups.google.com/group/sci.a..._frm/thread/1a
777a781e67a3a2/#)
indicates that there is no conclusive _observational_ evidence of q
becoming positive at z0.5.

That leads to a post by you, not by Rob.

No. It leads to a thread started by me which contains various postings
by Rob.

If you provide a complete ref,
with author and preferably arxiv, I will look at it.

The ref. provided by Rob was ApJ, 649, 563-569, 2006. I found the paper
by checking the contents of the most recent issues of the Journal. This
paper is less than 2 months old.
Authors: Charles Shapiro and Michael S. Turner . The ref. given by The
Astrophysical Journal at the top of the paper is 649:563-569, 2006
=A9 2006Date: Oct. 1 2006

Although, actually
The cosmological parameters are pretty well tied down by supernova
observations, and that should tie q=3Dq(t) down too. The only thing is, q
is used in a series expansion, which we don't much use any more, and it
makes not a lot of sense to use q(t) for any purpose I can think of.
What is usually discussed is q0=3Dq(t0), i.e. now.

If you are aware of different information, please clarify, with
appropriate references.

No, that is where I think we do have a problem. It's early days, and a=
ll
the data is too preliminary to be sure, but galaxy evolution models do
not tie in well with the age of the universe, when one looks at galaxi=
es
at z=3D6 and above. There are even large galaxies at z=3D10, though the
image we get of them is a bit inconclusive in terms of saying what kind
of stars they contain.

A reference for this too, would also be appreciated
#
I already gave you references in response to the above mentioned post.

I would refer you to two review papers in Natu

Glazebrook K. et. al., 2004, Nature, 430, 181-184.
http://www.pha.jhu.edu/~kgb/MiscPub/...iii-nature.pdf

Cimatti. et. al., 2004, Old Galaxies in the Young Universe, Nature, 430,
184-188. astro-ph/0407131

I had already read the first paper and the abstract of the second.
Neither support your assertion of large galaxies at z=3D10.

The first paper covers z =3D~ 0.5 to 2.

The second paper describes 4 galaxies at 1.6z1.9

I'll let you search arxiv yourself for galaxies around z=3D10. I don't
think there are many found so far.

I am only aware of 1, which was subsequently discredited. That is why I
asked you for your references.

Technical addendum.

In the above posting of Wed, Nov 22 2006 4:27 pm, the Astrophysical
Journal copyright symbol was corrupted to =A9. This is understandable
since it is an 8 bit character code, not 7 bit ascii. However, each
instance of =, including those quoted, was also corrupted, this time to
=3D. The reason for this is less obvious. (I found in a later posting
that this second corruption can be supressed by typing = over every
displayed =, before posting the response.)

John Bell

[Mod. note: MIME encoding (http://en.wikipedia.org/wiki/Mime) has this
effect. It can be avoided by posting in plain ASCII only, which is why
I continue to encourage posters to be careful to do so -- mjh]